This invention relates generally to the field of power-driven table saws including an arbor-mounted circular blade, or a flexible saw band which passes through an opening in the saw table which supports a workpiece. Devices of this general type are known in the art, and the invention lies in specific details of construction which provide improved accuracy with regard to maintaining a given adjustment, as well as improved ease in use.
When sawing wood, for example, it is normally very important to move the wood through the blade so that the axis of movement remains parallel to the plane of the saw blade at all times during the sawing operation. This insures that the blade will provide a good clean cut so that the cut wood surface will be smooth, requiring a minimum of sanding. The wood is guided by having its edge pressed against a guide or fence, the surface of which is parallel to the plane of the saw blade and set at a distance from the saw blade which will yield a cut workpiece of desired width.
As the means of holding the workpiece, conventional saw guides are clamped by various means to a fixed bar along the front edge of the saw table. This bar must be mounted so that it is exactly perpendicular to the plane of the saw blade. The movable fence is clamped to this bar by means of brackets, the design of which may vary, which are perpendicular to the axis of the fence. Such arrangements have several critical failings. Most importantly, the fixed bar must be exactly perpendicular to the saw blade. This is not always the case for a variety of reasons. The bar itself may not have been perfectly mounted. The bar may have shifted in position slightly over a period of time. The saw arbor may have shifted slightly so that it (and thus the blade) are no longer perpendicular to the bar.
Thus, the fence systems now in use which rely on this arrangement are all severely flawed in operation. In order for the fence to move in relation to the bar, there must be a bit of "play" between the fence bracket and the bar. At best, the fence is parallel to the saw blade only when it is clamped in position, a fact which makes adjustment and proper positioning of the fence quite difficult. In addition, there are often problems involved in simply sliding the fence along the guide bar to get it into the desired position. It frequently binds, and must be forced along the guide bar, thereby compounding the problems of parallel alignment abovementioned.